1. Field of the Invention
The present invention relates to a motor vehicle transmission system, and more particularly to a transmission system for use on a motorcycle or the like.
2. Description of the Relevant Art
Transmissions on some motor vehicles such as motorcycles have many gear positions. The driver of such a motor vehicle is therefore required to effect gear shifting frequently while at the same time operating the clutch and the accelerator when the motor vehicle is being driven.
One known transmission system for facilitating gear shifting is disclosed in U.S. Pat. No. 4,270,414. The disclosed transmission system has a gear shifting device which includes electric contacts that can be opened and closed by gear shifting operation. When the gear shifting device is in operation, the contacts are opened to inactivate an ignition circuit for an engine, so that the output power of the engine is reduced temporarily, e.g., for 0.1 through 0.2 second.
According to the disclosed transmission system, however, the output power of the engine is temporarily reduced irrespective of whether the transmission gears are shifted up or down. While the torque is being transmitted from the drive wheels to the engine such as when the motor vehicle is braked by an engine brake, the torque transmitted by the transmission mechanism is not reduced. Therefore, when the clutch is engaged again after the gear shift, the rotation of the output shaft of the engine may not be well synchronized with the rotation of the input shaft of the transmission mechanism, which corresponds to the rotation of the drive wheels. As a result, when the clutch is to be engaged again, it is necessary to engage the clutch gradually for smooth engagement.
The present invention has been made in an effort to effectively solve the problems of the conventional motor vehicle transmission system.